Early Modern Experimental PhilosophyA project of the Early Modern Thought Research Theme at the University of Otago

This is the final post on my first series on the debate between scholastics and novatores in early modern Spain. In the first post of the series I introduced two figures who had a heated debate concerning the status of astrology: Martin Martinez representing the novatores, and Diego de Torres Villaroel defending the scholastics. We saw that Martinez calls for a ban on astrology on methodological grounds. He criticizes those scholastics (specifically Villaroel) who rely on astrology for writing only from their imagination with no regard for observation and experiment.

In the second post of the series we looked at Martinez’s arguments in more detail. We focused on his rejection of the application of astrology in natural philosophy. His attack revolves around the claim that the astrologers explain natural phenomena by referring to obscure causes where the phenomena in question are clearly accounted for by referring to evident causes. He shows that in medicine and natural philosophy there is no need to consult the stars. Villaroel was offended by this attack on astrology and promptly published his reply, Entierro del Juicio Final, y vivificacion de la astrologia (Burial of the Final Judgment, and revitalization of astrology). Juicio Final was the title of Martinez’s attack, and in today’s post we will examine Villaroel’s attempt to bury it.

Villaroel sets out to respond to Martinez’s criticisms and show that astrology in fact is useful for our natural, moral, and political inquiries. We saw Martinez complain about the practice of placing celestial bodies as the causes of natural effects, in particular when it comes to explaining the ailments of the human body. Surprisingly, Villaroel responds to this criticism by saying that these are not mere conjectures, but are actually founded on observation and experience:

That Astrologers assign to each body part its Planet, or its star Sign, is not as dissonant as the Doctor [Martinez] judges; since in fact the analogy and conformity between the temper of the planets, and the cold, dry, wet, and warm parts of the wind, are such qualities not by the devotion of Astrologers, nor by their words, but because God made them that way, giving each its temper and quality: observation and experience, the mother of knowledge (which Martin lacks), has taught us so, as it taught our Masters; if not, let’s ask the Doctor: why is chicory cold? I believe he will answer, because God made it so, and gave it such quality. And I would ask further: has God told you which quality it has? No sir, he will answer (he is not so holy as to have revelations), experience has taught it to me and so have all Medical Authors. Well we astrologers say the same about the qualities of the Planets and Stars.

Despite Villaroel’s insistence that it is through experience and observation that astrologers know the qualities of the planets and their effect on the human body, there is no reference at all to an observation account to support the claim. Instead, Villaroel blames Martinez for not properly studying the work of the authors cited by astrologers (traditional scholastic figures, such as Aquinas and Galen), and so his ignorance leads him to his unfounded criticism.

In fact, it is this ignorance, Villaroel claims, that leads Martinez to think that astrologers refer to occult causes to explain natural phenomena:

I encountered then a Cartesian rascal, who told me with a hollow cough while stroking his beard: those influences you confer to the Stars are either occult qualities, which means you do not know if they exist, or they are evident qualities, and if so you are mistaken in not pointing them out. I replied to the Cartesian, identifying that his argument was as much of a cheat as him, and said: they are occult qualities to you, to Martin, and to all others who, not having studied them, ignore them completely, and because they appear occult to the ignorant, it does not follow that they do not exist, and they are evident qualities to those of us who have studied them, and we are not in error, since we point them out in our almanacs.

Villaroel insists on replying to the criticisms by pointing out Martinez’s supposed ignorance, and instead of supporting his argument with data, he focuses on quoting authors that recommend the study of astrology to insist that Martinez is not only ignorant, but also a terrible physician. Villaroel refers to passages from the work of Galen, Avicenna, and Hippocrates, where they all comment on the necessity of the study of astrology for the proper exercise of medicine. But other than the quotes, Villaroel’s claims are not backed up by observation and experience, despite his claims that such is the source of the astrologer’s knowledge.

This debate between Villaroel and Martinez has an interesting feature: it shows that there was more to the experimental/speculative divide than mere rhetoric. Both our authors use the rhetoric of the new philosophy, placing experience and observation as the only true source of knowledge; but while Martinez does refer to observational data to back up his explanations, Villaroel does not go beyond the authority of scholastic figures and their texts. What we have here is a clear case of the two sides in the ESD, where the experimental methodology supported by Martinez is contrasted with the speculative ways of Villaroel. Stay tuned for further posts on the ESD in early modern Spain!!

A while ago, Peter Anstey argued that, while the traditional rationalist-empiricist distinction (RED) is primarily about epistemology, questioning the foundational sources of knowledge, evidence and justification from an a priori, first-person perspective, the experimental-speculative distinction (ESD) is primarily methodological, concerned with how knowledge is generated. In this highly speculative post, we consider a consequence of preferring one of these distinctions over the other, namely, its effect on our understanding of philosophical progress in the early modern period. Note that the ESD is just one way of providing a methodological (as opposed to epistemological) narrative about the history of ideas, and we think much of what we have to say is perfectly compatible with those who, for instance, take a non-traditional (specifically, methodological or technological) stance on empiricism (see, for instance, Newton and Empiricism).

We suspect that the RED and the ESD give very different answers to questions about what the main driver of change in early modern philosophy was. Insofar as the RED gives us an account of what mattered in early modern philosophy, it generates stories about foundational, a priori investigation into the nature of knowledge. In contrast, the ESD tells a story of philosophical progress driven by scientific achievement, technological development and methodological innovation. These are two very different narratives about the history of ideas. Moreover, they emphasise the contributions of different historical figures.

When the focus is epistemology, we fixate on theorists who provided accounts of knowledge and its justification—namely, the canonical seven: Descartes, Leibniz, Spinoza, Locke, Berkeley, Hume and Kant—to the exclusion of other historical figures. The early Royal Society, for instance, clearly influenced the direction of Western thought, i.e. Western philosophical thought, enormously. Yet its members are sidelined in favor of epistemologists.

The ESD’s methodological emphasis shifts our focus. Boyle, Hooke and Newton, for example, did not produce new theories of knowledge, but they made strides in terms of methodology. Their inquiries yielded original ideas about how to produce knowledge and utilise new technologies (e.g. experimental apparatuses and mathematics). On this view, Newton made an enormous contribution to (anachronistically) philosophy as well as science. Newton synthesized Baconian experimental philosophy with the mathematical rigour of geometric methods—as we have argued on this blog, this methodology was influential beyond natural philosophy. Newton didn’t tell us what it is to know, but he did tell us how to go about generating knowledge. On the RED, scientific advancement is at best a side-show, on the ESD it is (to misquote Newton) the main business of philosophy.

This bit of speculation raises some questions.

Firstly, presumably it is a mistake to think that any one factor has played a privileged role in shaping history, intellectual or otherwise. Thus, arguing that the history of ideas is methodology-driven, rather than epistemology-driven, creates far too stark a dichotomy. If our speculation holds water, then the upshot is that the role of epistemology is over-emphasized. But how much, and how might we go about attributing blame?

Secondly, it is not clear to what extent frameworks such as the RED and the ESD should be read as hypotheses about historical forces. We might simply interpret them as handy heuristics—giving direction to various legitimate research interests. Moreover, they might bring out narratives relevant for understanding other parts of history. For example, one might argue that the RED is important for examining how later philosophers understood and were influenced by the early moderns (something like this view is defended here). So, how should we understand the content and role of such frameworks?

Thirdly, historians these days don’t often go in for ‘grand narratives’—and with good reason. Human history is messy and, typically, simplistic, one-size-fits-all explanations are inapplicable. Moreover, it’s not clear what difference such macro-scale frameworks make at the coalface of academic history, where historians and philosophers must engage with complex ideas and even more complex individuals. Prima facie, seeing Newton as an experimental philosopher rather than an empiricist won’t affect our interpretation of query 31. It might seem that the business of academic history is far too fine-grained for those differences to matter often. So, how much do such frameworks effect the day-to-day work of philosophers and historians?

Regardless of our answer to that question, we think these grand narratives do matter. They help decide the direction of research, and what counts as a good question for serious academic history of philosophy. Moreover, they influence pedagogy: how and what we teach (see our discussion here). Finally, they might play a role in how we, as contemporary philosophers, see ourselves and our field’s development.

This thought raises a further question: what role has the RED’s historical narrative played in vindicating and perpetuating the idea that ‘core’ epistemology targets questions about the nature of knowledge and its justification from a first-person a priori perspective?

So far, these speculations have raised more questions than answers. We’d love to hear your thoughts on them.

The mechanical philosophy, at least since the work of Marie Boas Hall and E. J. Dijksterhuis, has played a prominent role in the historiography of early modern natural philosophy. By contrast, experimental philosophy has been largely absent. Take, for example, Richard Westfall’s The Construction of Modern Science (Wiley, 1971). It has a whole chapter dedicated to the mechanical philosophy whereas the term ‘experimental philosophy’ appears only once in the entire book –– on the penultimate page –– and this is in a quote from Newton’s ‘General Scholium’ in a discussion of Newton’s concept of force and the term’s presence is irrelevant to Westfall’s narrative. It is also rather telling that the term ‘experimental philosophy’ does not even appear in the 662 pages of Floris Cohen’s The Scientific Revolution: A Historiographical Inquiry (Chicago, 1994).

It is interesting to reflect, therefore, that the English terms ‘experimental philosophy’ and ‘mechanical philosophy’ came into common use around about the same time, in the late 1650s. Moreover, when the new experimental philosophy emerged in England in the 1660s it was frequently associated with and even conflated with the mechanical philosophy. (Experimental philosophy was also commonly identified with corpuscular philosophy, though this is not our concern here.) Robert Hooke famously spoke of ‘the real, the mechanical, the experimentalPhilosophy’ in the Preface to Micrographia of 1665. By the end of the seventeenth century, however, the two had come to be fairly clearly demarcated. The Newtonian John Keill, for instance, lists four ‘sects’ of his day, two of which are the experimental philosophers and the mechanical philosophers (Introductio ad verum physicam, Oxford, 1702, p. 2).

The process by which this ‘decoupling’ occurred is quite convoluted and this is the first in a series of posts that will attempt to set out some points of reference from which we can understand how experimental philosophy and mechanical philosophy came to be clearly demarcated.

Let us begin with two Henrys, Henry More and Henry Stubbe. More was not a practitioner of experimental philosophy: in fact, he was not a natural philosopher at all. He was, however, a Fellow of the Royal Society. Stubbe was a physician and critic of the Royal Society and experimental philosophy. Now when Henry Stubbe attacked the Royal Society, and in particular its apologist Joseph Glanvill, he claimed that Henry More had given up his association with the Society because of the Society’s commitment to the mechanical philosophy which tended to atheism (Stubbe, Legends no Histories, London, 1670, p. 173).

More responded to Stubbe’s claims in a letter to Glanvill (c. 1671):

he [Stubbe] looks upon that Mechanick Philosophy which I oppose, to be the Philosophy the Royal Society doth profess, or would support. But the Philosophy which they aim at, is a more perfect Philosophy, as yet to be raised out of faithful and skilful Experiments in Nature, which is so far from tending to Atheism, that I am confident, it will utterly rout it and the Mechanical Philosophy at once, in that sense which I oppose, namely, as it signifies a Philosophy that professeth, That Matter having such a Quantity of Motion as it has, would contribute it self into all those Phaenomena we see in Nature. (Glanvill, A Praefatory Answer to Mr Henry Stubbe, p. 155)

More opposes a mechanical philosophy that is competent to explain everything and leaves no place for a deity. But this does not mean that he opposes mechanical explanations tout court. Alluding to a passage that Stubbe quotes from Thomas Sprat’s History of the Royal-Society of London he says:

I believe indeed most of us, I am sure my self does conceive, that Generation, Corruption, Alteration and all the Vicissitudes of corporeal Nature are nothing else but Unions and Dissolutions … of little Bodies or Particles of differing Figures, Magnitudes, and Velocities. But this thus bounded is not the Mechanical Philosophy, but part of the old Pythagorick or Mosaick Philosophy … (p. 156)

More is happy to acquiesce in corpuscular explanations, so long as their limitations are recognised. He goes on:

I think it is plain, what Mechanical Philosophy that is, that may incline Men to Atheism, and that is not the experimental Philosophy, which the Royal Society professes. (p. 157)

Clearly More accepts both the corpuscular explanations of a mitigated form of mechanism and experimental philosophy. Just how he conceives the relation between the two, however, is not clear from this letter.

When we turn to Stubbe we find a similar lack of differentiation. For example, earlier in Legends no Histories, Stubbe claims that no prince has ever been called great because he used ‘any knick-knacks of Experimental or Mechanical Philosophy alone’ (p. 4).

What these passages show is that for some writers the relation between mechanical philosophy and experimental philosophy was not clearly defined. They also illustrate how tempting it would be for those scholars who view the emergence of modern science through the lens of mechanism to reduce experimental philosophy to mechanical philosophy.

It may even be that part of the explanation of the relative neglect of experimental philosophy in the historiography of early modern natural philosophy is the tendency to conflate it with mechanical philosophy. In my next post I shall examine Robert Boyle’s view of the relation between mechanical and experimental philosophy.

Kant is generally considered to be the first philosopher who synthesized early modern rationalism and empiricism, and who, with this synthesis, set the terms of reference for much of nineteenth and twentieth century philosophy. Contrary to this view, I am currently writing a paper wherein I argue, first, that Kant never thought of himself as providing a synthesis of rationalism and empiricism but as providing a middle road between dogmatism and scepticism, and, second, that this middle road is provided precisely by rejecting the syntheses of rationalism and empiricism that he saw present in the dogmatic and skeptical traditions. Although the second of these theses is certainly more exciting, I will first need to shortly elaborate on the first thesis, and postpone a discussion of the second one to a later post.

A couple of simple searches through the works of Kant will reveal immediately that he never explicitly characterized his philosophy in terms of a synthesis of rationalism and empiricism. As has been argued on this blog, it was Reinhold who first propounded this reading of Kant’s critical philosophy – a reading which was then probably adopted by Wilhelm Gottlieb Tenneman in his History of Philosophy, but which actually took a far longer period of time to become the standard narrative in the historiography of philosophy. In “Kant on Empiricism and Rationalism”, Alberto Vanzo emphasized the fact that there are many passages spread throughout Kant’s works wherein he more or less explicitly sides with the rationalist tradition in his theoretical philosophy, ethics and aesthetics. However, important in this regard is Kant’s distinction between an immodest or dogmatic empiricism and a more moderate or scientific form of empiricism.

Immodest empiricism adopts “a principle of pure empiricism, not only in the explanation of appearances in the world, but also in the dissolution of the transcendental ideas of the world-whole itself” (A466/B494), whereas modest empiricism only adopts a principle of empiricism in the explanation of the phenomena in the sensible world and limits our speculative knowledge (Wissen) to this domain of sensible objects (A470-471/B498-499). Kant’s doctrine of the categories alone already implies a rejection of the immodest form of empiricism. However, Kant does not reject the modest form of empiricism (ibid.). My hypothesis is that he reconciled empiricism and rationalism neither by synthesizing them, nor by finding a middle road between them, but by relocating and limiting their principles and methods to different domains of objects and knowledge. The claim of modest empiricism that our knowledge must follow the guidance of experience is valid for the phenomena in the sensible world, which is the proper domain of theoretical scientific knowledge. But empiricism must withhold from making any dogmatic claims about non-sensible objects and the transcendental conditions of the possibility of experience, because this is the pure domain of philosophy proper. In this way Kant conceptually prepares the separation between the empirical sciences and rational philosophy proper, guaranteeing the autonomy of both. Accordingly, Kant’s real battle was never with empiricism as such, nor with rationalism, but with the dogmatic forms of both empiricism and rationalism.

Throughout his works Kant also argues that scepticism itself was merely a reaction to dogmatism, and he situates his own philosophy as the middle road between dogmatism and scepticism (see, for example, Kant’s unfinished Progress of Metaphysics and the introductions to the third and eight parts of Metaphysik Vigilantius). In my view, then, Kant does not reject empiricism as such, nor is he concerned with synthesizing empiricism and rationalism; his critical philosophy tries to walk the middle road between dogmatism and scepticism. Moreover, my further hypothesis is that according to Kant’s own diagnosis, the failures of the dogmatic and skeptical traditions derive from mixing up empirical cognitions with rational cognitions, so that it “is of the utmost importance to isolate cognitions that differ from one another in their species and origin, and carefully to avoid mixing them together with others with which they are usually connected in their use” (A842/B870), and that this critical project is precisely meant to counter the syntheses of rational elements with empirical elements that were prevalent in both traditions. But that would be a topic for a later post.

Currently, I am still in the process of writing the paper, so I would appreciate any comments or suggestions either on the blog or via email.

Following my previous post on the status of astrology in early modern Spain, I want to give a more detailed account of the debate between Martin Martinez and Diego Torres de Villaroel. In today’s post I want to focus on the specifics of Martinez´s rejection of astrology in Juicio final de la astrologia (the final judgment of astrology).

As I commented last time, Martinez directs his attack against Diego Torres de Villaroel, a scholastic mathematician and astrologist famous for his almanacs. Martinez attacks the use of astrology on three fronts: its application in natural philosophy, in morals, and in politics. Let’s focus only on the first of these aspects here.

Martinez complains that, in order to enhance the reach of their discipline, astrologers have placed celestial bodies as the cause of almost all natural effects:

…they [astrologers] confer to them [celestial bodies] the rains, winds, and all other alterations of the air. There is no metal in the depths of the earth that escapes their influence; they say Mars rules iron; the Moon rules silver, Jupiter rules tin, Saturn rules lead, Venus rules copper, and Mercury rues quicksilver… There is no animal, whether terrestrial, aquatic, or airborne, whose birth, life, and death does not depend on the judgment of the Celestial Bodies…even today, one or another Physician is possessed by this mistake, fixing to each celestial body its special qualities without ever experimenting them; just on their devotion, they make some hot and other cold; just on their word they make some dry and other wet; they assign a Planet to each body part: the Sun to the heart, the Moon to the brain, Mars to the liver, Saturn to the spleen, Venus to the kidneys, Jupiter to the uterus, and Mercury to the lungs…

Martinez first points out that, not being founded on experience, the conjectures of the astrologists lead to disagreements between them. One astrologist assigns the five moons of Jupiter to the fingers, while another assigns them to the five upper left teeth. Mocking the astrologists for the inconsistencies among their unfounded conjectures is only an initial stab at them, but Martinez has a more substantial philosophical argument behind it. The thrust of Martinez’s argument is that, given the presence of evident qualities, any reference to occult qualities can be nothing more than a fiction. The sun, the weather, and the observation of nature here on earth are enough to explain natural effects. There is no need to look for a connection between the celestial bodies and the ailments of the human body or the best times for harvest. The former are explained through medicine and the latter through natural philosophy, but astrology does not play any role in either.

To illustrate this, Martinez draws from natural phenomena and shows that natural philosophy always offers a better explanation than astrology. He refers to a particular event where we experience some warm days during winter as well as fresh days during summer. He emphasizes that not even the sun is a necessary cause of the seasons, but rather a sign of them. If the sun truly was the cause, then the temperature would gradually rise and decrease between the two solstices, and every year our summers and winters would be identical, given that the position of the sun is the same each year. So how do we explain the phenomenon? Astrologists, Martinez says, say that “the cold that we experience during summer is caused by the influence of the very cold Saturn, and the warm days during winter are due to the influence of raging Mars.” But if this were true, then this effect would be the same all across the globe, which is clearly false. Martinez refers to the different observations in Madrid and Valencia to illustrate the implausibility of the astrologists’ conjecture.

Natural philosophy offers a better explanation of this phenomenon: “the cause of these alterations is the variety of situations between Countries, and the variety of winds specific to each of them; since when the Austral blows in winter there is warmth, and when the Boreal blows in summer there is fresh climate…it is always necessary to refer to the specific constitution of the regions, and the diverse fermentations and other elemental alterations, in order to explain these phenomena, and reject the musings of the astrologists as unnecessary.”

Martinez drives the argument home by commenting on the superfluousness of consulting the stars when it comes to harvest:

Of the rains and storms I say the same, since when there is an evident cause, it is not philosophical to refer to obscure causes…We must think in the same manner regarding the infertility and abundance of harvests: for if the farmer, by manuring a ground which is watered promptly by rain, collects a bountiful harvest, we must not look at any Celestial body for the cause but rather to his diligence and the prompt rain; in the same manner we must account for the infertility of harvest by a defectuous watering, small crops, the locust plague, or other evident causes; but it is never necessary to refer to Celestial Bodies to explain such events.

In essence, Martinez appeals to the astrologists’ unfounded conjectures and their appeal to obscure causes to reject the application of astrology in our explanation of natural phenomena. However, the popularity of almanacs in Spain and the confidence and reputation of figures like Torres de Villaroel meant that Martinez was facing a fierce opposition. In my next post we will examine Torres de Villaroel’s defence of astrology and his subsequent attack on the novatores.

Recently, Zvi Biener and Eric Schliesser’s long-awaited volume, Newton and Empiricism, appeared on the shelves. The book is an excellent collection of papers, which makes a significant new contribution to the field. Today I want to focus on one aspect of this volume: the decision to frame the collection in terms of empiricism rather than experimental philosophy.

Over the last four years, we have provided many arguments for the superiority of the ESD over the RED. An important line of argument has been to show that ‘experimental philosophy’ and ‘speculative philosophy’ were the key terms of reference used by the actors themselves, and that they characterised their own work in terms of this division. For example, I have argued here, here, here and here that Newton is best understood as an experimental philosopher.

In their introduction, Biener and Schliesser explain their decision. They acknowledge the ‘Otago School’, and argue that, while in general there may be some good reasons to prefer the ESD to the RED, they see various problems with labelling Newton an ‘experimental philosopher’. Their concerns amount to the following: labelling Newton an ‘experimental philosopher’ obscures the idiosyncrasies of his approach to natural philosophy. They argue, firstly, that the label belies the significant influence of non-experimental philosophers on Newton’s methodology, for example those who influenced his mathematical focus. Secondly, that the label unhelpfully groups Newton with Boyle and Locke, when many features of his work support a different grouping. For example, Newton’s mathematical-system building suggests that his work should be grouped with Descartes’. Thirdly, they argue that the fact that Newton did not employ the label himself until after the publication of the first edition of the Principia suggests that he did not fully identify with the label.

These are important issues about the ESD and Newton’s place in it. So today I want to reflect on the broad problem of Newton’s idiosyncratic position. I argue that Newton’s divergence from Baconian tradition of the Royal Society is best seen as a development of experimental philosophy.

On this blog, I have sketched many features of Newton’s natural philosophical methodology. I have argued that, if we look at Newton from within the framework of the ESD, he can be neatly and easily identified as an experimental philosopher. His use of queries, his cautious approach to hypotheses, and his many methodological statements decrying the construction of metaphysical systems, suggest that this is a label that Newton would have been comfortable with. However, there is an important caveat to note: while Newton was clearly influenced by the Baconian experimental tradition, he did not consider himself a Baconian experimental philosopher.

In the earliest statements of his mathematico-experimental approach, Newton set up his position in opposition to the Baconian experimental philosophers. In these passages, one feature of Newton’s methodology stands out in explicit rejection of the Baconian method: his claims to certainty. This feature, in itself, is not very significant – many experimental philosophers believed that, in the end, natural philosophy would be a form of scientia, i.e. a system of knowledge demonstrated from certain axioms. Indeed, Bacon shared this ideal of certainty. He thought that his method of induction could get around the problems usually associated with ampliative inference and deliver knowledge of the essences of things. Thus, Bacon’s method of natural history was ultimately supposed to provide the axioms on which scientia could be founded. The challenge, which everyone agreed on, was to discover those axioms on which the system would be built.

Newton and the Baconians seem to diverge on their responses to this challenge. Baconian experimental philosophers recommended that one should have all the facts before formulating generalisations or theories. In contrast, Newton thought that a few, or even just one, well-constructed experiment might be enough – provided you used it in the right way. This shows that Newton took a different view of the role of evidence in natural philosophy. This divergence amounts to three key differences between Newton and the Baconian experimental philosophers:

Where the Baconian experimental philosophers advocated a two-stage model, in which construction of natural histories preceded theory construction, Newton appeared to reject this two-stage approach. Newton commenced theory-building before his knowledge of the facts was complete.

For the Baconian experimental philosophers, queries were used to give direction and define the scope of the inquiry. But Newton’s queries were more focussed on individual experiments.

There is strong textual evidence that the ESD was operative in Newton’s early natural philosophical work. We have good reason to suppose that Newton regarded his natural philosophical pursuits as experimental philosophy. This becomes clearer in Newton’s later work. For instance, in the General Scholium to the Principia (1713), Newton explicitly described his work as ‘experimental philosophy’ – indeed, Peter Anstey has noted that Roger Cotes also recognised this feature of Newton’s work. We also have good reason to suppose that, in important ways, Newton saw his work as aligned with the Royal Society and, by extension, with the Baconian movement. But Newton was also a mathematician, and he saw a role for mathematical reasoning in experimental philosophy. In many ways, it was this mathematical approach that led to his divergence from the Baconian experimental philosophy.

Biener and Schliesser are right to draw attention to the ways in which Newton’s position diverged from the experimental tradition of the Royal Society. However, they fail to recognise that Newton’s position diverged in a way that should be viewed as a development of this tradition. Indeed, the ‘Newtonian experimental philosophy’ eventually replaced the experimental philosophy of Boyle, Hooke and the other early members of the Royal Society. The label ‘empiricism’ has no such historical relevance. But, more on this another time…

In my last post I discussed the astronomer James Bradley who taught experimental philosophy in Oxford from 1729 until 1760. Since then I have examined Bradley’s extant lectures in the Bodleian Library, Oxford.

One of the most interesting features of the lectures is the manner in which the distinction between experimental and speculative philosophy is presented at the very beginning of his opening lecture. Bradley commences with a general reference to the laws of nature:

/1/ … these are no otherwise to be discovered than by experiments & observation & examining the Phaenomena & finding from them by what /2/ laws their motions are ordered & regulated. which is properly the Business & scope of Natural & Experimental Philosophy. (Bodleian Library MS Bradley 1, p. 1 (Used with permission of Bodleian Libraries, University of Oxford)

This view of natural philosophy is interesting in so far as it places laws of nature and experiment to the fore in a manner that was not possible before the advent of Newton’s Principia. Bradley continues:

But then our principal endeavour must be to learn the true & real manner in which the operations of Natur are actually performd & not content ours[elves] with framing Hypoth[eses] to explain how such Phaenom[ena] may be perform’d tis on this account that Reasoning much from Hypotheses in Natural Phil[osophy] is apt to lead people into mistakes and there is no likelier a method to avoid error than having recourse to experiments & trials (Bodleian Library MS Bradley 1, p. 2 (Used with permission of Bodleian Libraries, University of Oxford)

Note here the rhetoric of experimental philosophy: the warning against ‘framing Hypotheses’ which can lead to error, and the emphasis on experiment and observation. Bradley then expresses a form of fallibilism in his claims about the epistemic status of knowledge acquired by the method of ‘experiments & trials’:

/3/ Tho this is no doubt the most likely method of coming at the truth yet even in this manner of proceeding we must not expect to meet with Proof in Natural Philosophy so absolutely convincing as in pure mathematics because the Ideas we have to do with in Mathematics are the Productions of the mind itself & therefore we may have a more full adequate knowledge of them than of those we have in natural Philosophy which being fram’d from things without us they may not be just & consequently our deductions & reasonings about these may be liable to some uncertainty & leave some scruple upon the mind. (Bodleian Library MS Bradley 1, p. 3 (Used with permission of Bodleian Libraries, University of Oxford)

Bradley is honest in his claim that one should not expect mathematical certainty in matters of experimental natural philosophy. Yet he also believes that there are measures that one can take to assure us that our inferences from experiments are secure:

In order to remove all scruple as much as possible & that the mind may assent to the conclusions drawn from facts & experiments in searching into the operations of nature Sir I. Newton lays down the following Rules of Arguing in Natural Philosophy. (Bodleian Library MS Bradley 1, p. 3 (Used with permission of Bodleian Libraries, University of Oxford)

He then summarises the four rules of philosophising that Newton first published in the second edition of the Prinicpia.

What Bradley is providing in his very first lecture is a methodological statement that reveals his conception of natural philosophy and the means by which one acquires the knowledge of nature. This is what generations of students were taught at Oxford when they enlisted in his courses in the Old Ashmolean Museum. Now there are some scholars who question the value of the experimental/speculative distinction as terms of reference for understanding early modern British natural philosophy. It is necessary, however, to ask what more it would take for the ESD to be taken seriously than a lecture on natural philosophy that was repeated at least 79 times over twenty-one years to inquisitive university students at Oxford University who were paying to be taught experimental philosophy by an eminent practitioner. This is not empty ‘method talk’, this is not the RED, the rationalism/empiricism distinction, in disguise. These are the actors’ terms of reference, and they are not in polemical writings, or in promotional puffs prefacing controversial works in natural philosophy, but in ordinary undergraduate lectures.

In one of my previous posts regarding early modern Spain I referred to Martin Martinez, a physician who was an avid promoter of the experimental method. Today I want to examine a debate he had regarding the rejection of astrology. In this blog we have provided many illustrations of the methodological statements typical of those who promoted and adopted experimental philosophy. We have shown the insistence in rejecting the work of those that rely solely on speculation, but we have not yet seen any examples of the work of speculative philosophers. The case of astrology in 1720s Spain can shed some light on the kind of speculative science rejected by experimental philosophers like Feijoo and Martinez.

Besides the comments he added supporting Feijoo’s work, Martinez wrote a whole essay (Juicio final de la astrologia (The final judgment of astrology)) rejecting astrology in 1727. He distinguished between astronomy and astrology: while in the former “the regular movement of the stars is observed…times are computed, lunar cycles determined, and eclipses are predicted”, in the latter astrologists “feign a volume (only intelligible to them) in the heavens where they find written mundane events, wars, famine, pests, shipwrecks, harvests, diseases, and all other fortunes of human life.”

In the comments he makes defending Feijoo’s work, Martinez clarifies that the problem with astrology is that it is not founded in observation and experience:

“Upon reflection, according to what reasoning, or experience, do the astrologists found their imagined influxes of the stars and planets? On what grounds do they know that Mars burns, and Saturn cools? They probably say, because Mars is red and Saturn grey: though according to this they should also say that carnations burn and quicklime cools; and if they say they experience heat coming from Mars, I do not understand how they know it comes from it, and not from another cause.”

Martinez goes on listing a number of claims astrologists make, in particular related to the effects the movement of the planets and stars, eclipses, and comets have on the health of individuals. But Martinez is directing his claims to one individual in particular, Diego de Torres Villaroel, a mathematician and astrologist who published yearly almanacs with predictions under the pseudonym “el gran Piscator de Salamanca”. Leaving the calendars aside, Torres also published an essay containing his ideas on the nature of the earth and the heavens. The text was first published in 1724 under the title Viaje fantastico del gran Piscator de Salamanca (The fantastic journey of the great Piscator of Salamanca), and then again in 1739 as Anatomia de todo lo visible e invisible (Anatomy of all that is visible and invisible). It is this book that Martinez targets, and will serve as our illustration of the kind of speculative philosophy the novatores rejected.

Torres’ essay gives an account of the structure and composition of the earth and the heavens, all this prompted by an eclipse which occurred on May 22, 1724. The explanation of the constitution of both spheres of the universe (heaven and earth) is given through a story where the great Piscator travels to the depths of the earth and then upwards to the heavens, illustrating to his fellow travellers all the details of both spheres. As is clear from various passages, Torres’ claims are never supported by observations, but only by the musings of his mind and astrological calculations. The opening lines of the dedicatory epistle highlight the speculative nature of the work:

“Hand over hand the soul, without resorting to the use of the external senses, and reason, in arms of a jobless idleness, let fantasy to its word, and running through the spaces of imagination it recited in their theatre the following story.”

Torres acknowledges that he writes from his imagination, but asserts that he reaches the same conclusions others (like Kepler, who studies “the cosmic machine”) have:

“With no other guide but my imagination, and sleeping like a log, I have completed the same journeys [as Kepler and Kircher].”

Although lines like the ones just quoted give the impression that Torres must be speaking metaphorically, it seems that his ‘discoveries’ had no other foundation that the inspiration he got from studying astrology. In the opening lines of the story, a character contrasts the method of astrologists like Torres to those who studied the eclipse by means of observation:

“How is it that you, Mr. Astrologist, in an eclipse whose nature and effects have excited the North and their less lazy Observers have been writing about, you do nothing other than note down in your Prediction the simple calculation of the time and the day?”

Torres defends himself, and convinces his companions to go on a journey through the earth and the heavens in order to understand the nature of eclipses and their effects on human events. In their journey through the earth the astrologist points out where hell and purgatory reside deep down where there is no influence of the heavenly bodies. Then they travel upwards to the heavens, where the astrologist explains the different levels, how all is made of ether, and its effects on the earth. He explains how when a comet is “of the nature of Saturn”, it “causes colds, leprosy, haemorrhoids, paralyses, and chronic diseases”; if it is dominated by Mars on the other hand, it causes “cruel dysentery, rotten fevers, delirium, haemorrhages…”

I could go on drawing on passages from Torres’ book, but the ones quoted above are enough to illustrate the opposition to astrology that the Spanish novatores insisted on. It is important to remember that figures like Feijoo and Martinez had a genuine worry regarding the influence of astrology. Unlike our present time, in the early decades of the eighteenth century astrology was still considered by many as a genuine science, and it was this (more than the almanacs) that motivated the novatores to call for a ban on astrology.

Colloquium Sponsors:

This colloquium forms part of Professor Peter Anstey’s ARC Future Fellowship project on ‘The nature and status of principles in early modern philosophy’. It is sponsored by the School of Philosophical and Historical Inquiry and the Sydney Centre for the Foundations of Science.

In my last post, I considered the experimental support Newton offers for his laws of motion. In the scholium to the laws, Newton argues that his laws of motion are certainly true. However, in support he only cites a handful of experiments and the agreement of other mathematicians. I suggested that the experiments discussed do support his laws, but only in limited cases. This justifies their application in Newton’s mathematical theory, but does not justify Newton’s claims to certainty. In this post, I will speculate that the laws of motion were in fact better established than Newton’s discussion suggests. I introduce the notion ‘epistemic amplification’ – suggesting that Newton’s laws gain epistemic status by virtue of their relationship to the propositions they entail. That is, by reasoning mathematically from axioms to theorems, the axioms obtained higher epistemic status, and so the reasoning process effectively amplified the epistemic status of the axioms.

I am not arguing that epistemic amplification captures Newton’s thinking. In fact, Newton explicitly stated that epistemic gain was not possible. For him, the best one could achieve was avoiding epistemic loss. (I have discussed Newton’s aims of certainty and avoiding epistemic loss here and here.) I suggest that, objectively speaking, the epistemic status of Newton’s laws increases over the course of the Principia.

The specification of the laws as the axioms of a mathematical system; and

The justification of laws as first principles in natural philosophy.

Let’s consider the first project. In addition to the support of mathematicians and the experiments that Newton cites, it is plausible that the epistemic status of the laws increases by virtue of their success in the mathematical system: in particular, by entailing Keplerian motion. Kepler’s rules and Newton’s laws of motion have independent evidence: as we have seen, Newton’s laws are weakly established by localised experiments and the ‘agreement of mathematicians’; Kepler’s rules are established by observed planetary motion and were widely accepted by astronomers prior to the Principia. Newton’s laws entail Kepler’s rules, which boosts Newton’s justification for his laws. Moreover, Newton’s laws provide additional support for Kepler’s rules, by telling us about the forces required to produce such motions. The likelihood of the two theories is coupled: evidence for one carries over to the other. So Newton’s laws also boost the justification for Kepler’s rules. Thus, Newton achieves epistemic gain: the epistemic status of the laws, qua mathematical axioms, has increased by virtue of their relationship to Kepler’s rules.

Now let’s consider the second project – the application of the laws to natural philosophy. Again, the discussion in the scholium justifies their use, but not their certainty. I now suggest that these laws, as physical principles, gain epistemic status through confirmation of Newton’s theory. This occurs in book 3, when Newton explicitly applies his mathematical theory to natural phenomena. As I have previously discussed, the phenomena (i.e. the motions of the planets and their moons) are employed as premises in Newton’s argument for universal gravitation. However, the phenomena also support the application of the mathematical theory to the physical world: they show that the planets and their moons move in ways that approximate Keplerian motion. As we saw above, the laws of motion entail Kepler’s rules. So, since the phenomena support Kepler’s rules, they also support the laws of motion. So this is a straightforward case of theory-confirmation.

There is also scope for theory-testing in book 1. Each time Newton introduces a new factor (e.g. an extra body, or a resisting medium), the mathematical theory is tested. For instance, the contrasting versions of the harmonic rule in one-body and two-body model systems provides a test: it allows the phenomena to empirically decide between two theories, one involving singly-directed central forces, the other involving mutually-interactive central forces. Similarly, the contrasting two-body and three-body mathematical systems provide a test: they allow the phenomena to select between a theory involving pair-wise interactions and a theory involving universal mutual interaction. Moreover, in the final section of book 2, Newton shows that, unlike his theory, Cartesian vortex theory does not predict Keplerian motion. Thus, the phenomena seem to support his theory, and by extension the laws of motion, and to refute the theory of vortices. Again, the laws seem to gain support by virtue of their relationship to the propositions they entail.

To summarise, Newton claims that his laws are certainly true, but the support he gives is insufficient. Here, I have sketched an account in which Newton’s laws gain epistemic status by virtue of their relationship to the propositions they entail. ‘Epistemic amplification’ is certainly not something which Newton himself would have had truck with, but the term does seem to capture the support actually acquired by Newton’s laws in the Principia. What do you think?

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